NOT FOR PUBLICATION

PER CURIAM.

Plaintiffs Steven Kowaleski and his parents, Robert and Lucille Kowaleski, appeal from a May 13, 2011 order that barred their expert's report as a net opinion and granted defendants' motions for summary judgment. Plaintiffs' complaint sought damages from defendants George Wolff, Michelle Swisher, and the Morris-Union Jointure Commission Developmental Learning Center (MUJC) under the New Jersey Tort Claims Act, N.J.S.A. 59:1-1 to 12-3. Plaintiffs alleged that twenty-four-year-old Steven, who is autistic, experienced post-traumatic stress disorder as a result of physical abuse inflicted by Wolff, a teacher formerly employed by MUJC. Plaintiffs further alleged that Swisher, Wolff's teaching assistant, failed to properly "care for and otherwise provide for the safety of" Steven. For the reasons that follow, we affirm.

When Steven was three years old, the Westfield Child Study Team classified him as Pre-School Handicapped and he was enrolled in Edison's Pre-School Handicapped class, where he received speech and occupational therapy. In February 1992, when Steven was four years old, he was diagnosed with Pervasive Developmental Disorder and placed in a program at Children's Specialized Hospital designed to meet the specific needs of children with autistic behaviors. Steven attended kindergarten at the Midland School, where he continued to receive speech and occupational therapy. A psychological evaluation conducted by a school psychologist on January 31, 1996, when Steven was eight years old, found that he was "an essentially happy youngster who enjoy[ed going] to school," but that he had been known to "kick out" when he was "particularly frustrated."

After several years at the Midland School, Steven began experiencing "increasing behavioral difficulties" and the Office of Special Services for the Westfield Public Schools referred Steven to Lawrence DeMilio, M.D., for a psychological evaluation. In his report, dated February 21, 2004, Dr. DeMilio noted that Steven had "been seen by both school officials and his parents as more difficult and more irritable." Specifically, Steven had become "more argumentative and much more irritable toward faculty," and "more agitated." Steven's mood was described as "tense" and he had "very low frustration tolerance." Dr. DeMilio, however, noted that Steven's behavior did not escalate "to any physical type dangerousness."

On October 16, 2004, Dr. DeMilio conducted a follow-up evaluation because of continuing problems with Steven's behavior at the Midland School. Steven had been "having periods of rapid, out of proportion and at times difficult to manage sense of tension." Steven was "frequently pacing out of the [classroom], looking tense, [and] looking almost `panicky.'" During these episodes, Steven sometimes "struck students, usually with an open hand, usually on the back." Dr. DeMilio did not believe that Steven had an "intent to harm," but he found Steven's behavior to be "totally inappropriate." In response to Steven's behavior, school staff tried "to remove him from class," "separate him for time-outs," and "to talk him down." Dr. DeMilio noted that Steven's teachers felt "stretched, almost [to] their limits[,] in terms of managing Steven in a safe manner." Eventually, Steven's behavior became so uncontrollable that he was removed from the Midland School.

In January 2005, when Steven was seventeen years old, he was enrolled in MUJC, which provides public school programs for children with autism. At MUJC, Steven continued to have problems with his behavior. For example, on March 7, 2005, he hit another student on the way to lunch; on June 9, 2005, he hit and kicked other students on the school bus; on June 30, 2005, he hit and spit on the school aides and tried to open the emergency exit on the school bus; on August 3, 2005, he threw trash at another student; and on September 19, 2005, he hit another student and attempted to hit several MUJC staff members. Wolff became Steven's teacher in July 2005.

In the fall of 2006, Steven's parents noticed that his "behavior started to regress." He began "yelling" and "screaming" and "having some really bad... behavior problems." In November 2006, Steven returned home from school one day and told his mother that Wolff had hit him. In response, the Kowaleskis first spoke with Steven's case manager, Nathan Hollis, and then they "brought it to the school's attention."

On January 24, 2007, a meeting was held at MUJC between the Kowaleskis, Wolff, Swisher, Hollis, and school administrator Barbara Starling. At the meeting, the Kowaleskis expressed their concern regarding Steven's behavior and the "allegations of excessive force" by Wolff. The Kowaleskis were "assured by everyone present that those allegations were not true," and that it was just "Steven's perspective of the situation." Wolff explained "there were times when he had to restrain Steven from hurting himself or someone else" and it "appear[ed] that Steven [did] not like to be touched." The meeting ended with Wolff being encouraged to "first speak with Steven as a way of calming him."

On June 5, 2007, Miriam Calabrese and Jill Chmiel, who were teaching assistants at MUJC, wrote letters to the school's administration regarding Wolff's aggressive response to Steven's behavior. Calabrese noted that when Steven exhibited problematic behavior, Wolff would "grab Steven by his shirt" and "with both fists[,] push really hard into Steven's throat." Calabrese characterized this as "a form of choking." Calabrese also alleged that Wolff "put his forearm into Steven's throat and pushed him hard enough that Steven's head... slam[med] against the wall." According to Calabrese, Wolff's aggressive behavior towards Steven "began sometime in early winter."

Chmiel alleged in her letter that she had seen Wolff "hit Steven... with a closed fist repeatedly in the head when Steven is having behaviors." Chmiel also alleged that Wolff would "grab Steven by the neck of his shirt and proceed to put his two fists hard into Steven's throat choking him." In addition, Chmiel indicated that if Steven got an answer to a question wrong, Wolff would elbow him "in the side of the face hard enough that [his] head would bang into the wall." According to Chmiel, Wolff's "aggressive behavior" occurred "several times a month."

Barbara Starling and Ethel Kozlik, another MUJC administrator, met with Wolff on June 5 and 6, 2007, to discuss Calabrese's and Chmiel's allegations. Wolff denied the accusations, but he admitted that on one occasion he "had to grab [Steven] and pull him out of the bathroom." On June 7, 2007, Starling and Kozlik sent Wolff a letter summarizing the issues they had discussed. The letter also contained a "Corrective Action Plan" to address Wolff's behavior toward Steven.

On June 8, 2007, the Kowaleskis, Starling, and Hollis met to discuss the allegations against Wolff. At that meeting, Starling assured the Kowaleskis that MUJC took "such allegations extremely seriously" and that they had "instituted a rigorous investigation" regarding the claims. In addition, Steven was transferred "from his existing classroom to another appropriate classroom setting."

On June 11, 2007, the Kowaleskis contacted the New Providence Police Department to report the incidents that had occurred between Wolff and Steven. Also on June 11, 2007, the Kowaleskis called MUJC to inform the school that "Steven was feeling under the weather" and that he "would be out of school for the next week."

On June 18, 2007, Kim Coleman, MUJC's superintendent, sent a letter to Wolff informing him that he was suspended with pay pending the outcome of her investigation and the investigation by the New Providence Police Department. Following her investigation, Coleman sent a letter to Wolff advising him that she would be recommending that the MUJC Board of Education terminate his employment. On August 28, 2007, Wolff pled guilty to assaulting Steven on four separate occasions in violation of a New Providence Borough ordinance. He resigned from his teaching position the same day.

In September 2008, Steven was enrolled in the Douglass Developmental Disabilities Center, a special education program at Rutgers University for students with autism. Steven attended the program for one year, at which point he aged out. While there, he did "very well" with only a "few incidents."

On May 13, 2009, Steven and his parents filed a complaint in the Law Division alleging that Wolff physically abused Steven causing him serious and permanent psychological harm. In support of their claims, the Kowaleskis relied on a two-page report from R. Christopher Stucky, M.D., dated November 18, 2010, which described his treatment of Steven following the incidents at MUJC.

Dr. Stucky first met with Steven on June 6, 2008, and they had regular sessions "one time per month" for fifty minutes each session. After a brief three-sentence review of Steven's history, Dr. Stucky asserted that prior to attending MUJC "Steven's mood and behavior were not a problem and the parents did not seek mental health services until their son was placed at [MUJC]." Dr. Stucky also incorrectly stated that Steven attended MUJC for "eighteen months."

According to Dr. Stucky, Steven's behavior "deteriorated" and became "increasingly violent" during his time at MUJC. Dr. Stucky noted that Steven began to "yell, punch and kick" and that such behavior was "atypical" for Steven. Dr. Stucky also noted that after Steven was removed from MUJC and enrolled in the Douglass Developmental Disabilities Center, he "continued to have aggressive outbursts in school, but they were less frequent," and that he "still had and continues to have aggressive outbursts at home."

Dr. Stucky diagnosed Steven with "post-traumatic stress disorder secondary to the physical and verbal abuse he experienced at [MUJC]." Dr. Stucky stated that even with medication and therapy, Steven's "behavior remains very difficult to manage and will continue to be so into the future. Steven's prognosis is guarded at best."

Defendants' expert, David J. Gallina, M.D., also conducted a psychological examination of Steven. Dr. Gallina stated in his report, dated February 10, 2011, that the most predominant symptom of post-traumatic stress disorder is "the re-experiencing of the trauma," not "anxiety or avoidant behavior." Additional symptoms include "intrusive thoughts or nightmares of the event, startled reactions, psychic numbing, and survival guilt." Dr. Gallina found that "[d]uring discussions of the incidents in question and subsequent treatment, there was no avoidance noted" and that "[t]here was no particular emotion display [from Steven] while discussing these issues." Thus, Dr. Gallina concluded that Steven "does not have Post-Traumatic Stress Disorder."

Dr. Gallina found that Steven's history indicated that his "difficulties and treatments existed prior to the incidents in question" and that, therefore, they were "unrelated to that incident." Dr. Gallina also found that Steven's "current difficulties are an extension of problems that he experienced prior to the incident in question," and there was "no evidence... that Steven's underlying and preexisting difficulties are currently exacerbated by the incident in question." In Dr. Gallina's opinion, Steven's functioning was "compatible with his overall preexisting diagnostic and clinical state."

After the discovery period had ended, defendants filed motions to strike Dr. Stucky's report as a net opinion and for summary judgment. Following oral argument, the trial court granted defendants' motions, reasoning as follows:

Thus, the court concluded that Dr. Stucky's report was an inadmissible net opinion. In addition, the court concluded that without expert testimony, plaintiffs could not differentiate between Steven's preexisting condition and any psychological harm that may have resulted from Wolff's actions. Accordingly, summary judgment was entered in favor of defendants.

On appeal, plaintiffs argue that the court erred when it determined that Dr. Stucky only provided a net opinion. Plaintiffs also claim that the court should have conducted a Rule 104 hearing prior to ruling on the admissibility of Dr. Stucky's report. Based on our review of the record and the applicable law, we conclude that summary judgment was properly granted and that plaintiffs' arguments are clearly without merit. R. 2:11-3(e)(1)(E). We add only the following comments.

A trial court's grant of summary judgment is appropriate where "the pleadings, depositions, answers to interrogatories and admissions on file, together with the affidavits, if any, show that there is no genuine issue as to any material fact challenged and that the moving party is entitled to a judgment or order as a matter of law." R. 4:46-2(c). When reviewing a trial court's grant of summary judgment, an appellate court utilizes the same standard applied by the trial court. See, e.g., Prudential Prop. & Cas. Ins. Co. v. Boylan, 307 N.J.Super. 162, 167 (App. Div.), certif. denied, 154 N.J. 608 (1998). We must first determine "whether the competent evidential materials presented, when viewed in the light most favorable to the non-moving party, are sufficient to permit a rational factfinder to resolve the alleged disputed issue in favor of the non-moving party." Brill v. Guardian Life Ins. Co. of Am., 142 N.J. 520, 540 (1995). If there is no genuine issue of material fact, we must then decide whether the trial court's application of the law was correct. Id. at 537.

When reviewing an evidentiary ruling and a summary judgment, we must "address the evidence decision first." Estate of Hanges v. Metro. Prop. & Cas. Ins. Co., 202 N.J. 369, 385 (2010). The evidentiary ruling is reviewed under an abuse-of-discretion standard, and the legal conclusions supporting the summary judgment decision are reviewed de novo. Ibid.

Under the New Jersey Tort Claims Act, N.J.S.A. 59:1-1 to 12-3, a claimant may recover damages for pain and suffering "against a public entity or public employee" only if the claimant suffered a "permanent loss of a bodily function... where the medical treatment expenses are in excess of $3,600.00." N.J.S.A. 59:9-2(d). A substantial permanent psychological injury may qualify as a permanent loss of a bodily function. See Collins v. Union Cnty. Jail, 150 N.J. 407, 420 (1997) ("We hold that plaintiff's claim of alleged permanent psychological harm in the form of post-traumatic stress disorder resulting from the rape by the corrections officer, constitutes a `permanent loss of a bodily function' within the meaning of N.J.S.A. 59:9-2(d).").

A diagnosis of post-traumatic stress disorder requires expert testimony. See, e.g., State v. Hess, 207 N.J. 123 (2011); State v. Briggs, 349 N.J.Super. 496, 500 (App. Div. 2002). Expert testimony is also necessary to prove that a causal link exists between post-traumatic stress disorder and allegedly tortious conduct. See, e.g., J.W. v. L.R., 325 N.J.Super. 543, 548 (App. Div. 1999) (finding that expert testimony was necessary to demonstrate that alleged sexual abuse caused a particular psychological condition).

A witness qualified as an expert may testify "in the form of an opinion or otherwise." N.J.R.E. 702. However, an expert's opinion must be based upon "[t]he facts or data in the particular case." N.J.R.E. 703. An expert's "bare conclusions, unsupported by factual evidence or other data, are inadmissible as a mere `net opinion.'" Biunno, Current N.J. Rules of Evidence, comment 3 on N.J.R.E. 703 (2011); see also Buckelew v. Grossbard, 87 N.J. 512, 524 (1981). The net opinion rule "`requires an expert to give the why and wherefore of his or her opinion, rather than a mere conclusion.'" State v. Townsend, 186 N.J. 473, 494 (2006) (quoting Rosenberg v. Tavorath, 352 N.J.Super. 385, 401 (App. Div. 2002)). A net opinion can result from the "failure of the expert to explain a causal connection between the act or incident complained of and the injury or damage allegedly resulting therefrom." Buckelew, supra, 87 N.J. at 524.

In the present matter, we agree with the trial court's determination that Dr. Stucky's report was an inadmissible net opinion because he failed to explain the basis for his post-traumatic stress disorder prognosis; he failed to differentiate Steven's present condition from his preexisting condition; and he failed to state that Steven's injury was permanent. Therefore, plaintiffs were unable to satisfy the requirements of N.J.S.A. 59:9-2(d) and defendants were entitled to summary judgment as a matter of law.

Affirmed.